In the mining industry, heavy equipment is powered using mining cables and couplers that provide a three-phase, deadbreak, plug and socket style connection. The couplers are typically used to terminate SHD-GC mining cables that carry three phase conductors, at least one ground conductor and at least one pilot conductor. Each of these conductors are multi-stranded Class I or DLO cable that can have about 1225 strands for a 500 kemil wire.
The conductors are terminated on a suitable connector to make the electrical connection. The connectors typically include a plug or pin member that mates with a socket or receptacle member. Each of the plug and socket connector members have previously used a two-piece design having a front mating part (or front end portion) and a rear cable part (or rear end portion) that are threadingly engaged and possibly sealed to help prevent moisture from entering the connector.
The front end portions of the connectors typically use a tulip (finger-style) or a louvertac band (multilam) style contact interface. The tulip style interface has a high mating force issue and requires a closing tool during connection. The tulip style interface also introduces breaks in contact between the fingers (i.e., the contact between the plug and socket is not continuous). The louvertac band style interface requires less force during mating but there are concerns about performance under contaminated conditions that are found in a mine. The louvertac band style interface also can have breaks in contact due to offset issues associated with the multilam design.
The rear end portions of the connectors are typically soldered due to the fine-stranded nature of the cable. This requires skilled labor and introduces contact pressure repeatability problems (e.g., due to cold solder resulting in poor contact pressure). Another approach has been to use hex bolts that are tightened by an allen wrench. However, it is difficult to consistently tighten the bolts to the specified torque to ensure the proper contact pressure.